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.DOUGAN.

VERTICAL AIR COMPRESSOR.

APPLICATION FILED MN. I6. 1909- RENEWED .IAN L 19.19I6.

Patented Aug. 22, 1916.

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K. DOUGAN.

VERTICAL AIR COMPRESSOR. APPLICATION mso MN. I6. |909. RENEwED 1AN. 19. |916.

Patented Aug. 22, 1916.

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KENNEDY DOGAN, or MINNEAPOLIS, MINNESOTA.

' VERIICAI. AIR-COMPRESSOR.

Speclcation of Letters Patent.

Patented aug. es, 191e.

Application filed January 1G, 1909, Serial No. 472,666. Renewed January 19, 1916. Serial No. 73,082.

To all whom it may concern: z

Be it known that I, KENNEDY DOUGAN, .a citizen of the United States, and resident of Minneapolis, in the county of Hennepin and `State of Minnesota, have invented Vcertain new and useful Improvements infl7 ertical Air-Compressors; and I do hereby declare the following to be a full, clear, and exact description of the invention', such as will enable others skilled in the art to which it appertains to make and use the same.`

The general object of this invention is to provide a direct acting vertical air compressor that will use steam expansively and have higher eliiciency than the best type of ily-wheel air compressor.

A further object vis to provide a combined high pressure and lowv pressure air compressor, having easy manual adjustment for same and for any intermediate pressure.

In the compressorv herein disclosed, the pistons are thrown Yup by steam pressure and driven down by a heavy weight attached thereto. The steam is automatically cut oli at the point required to carry the pistons to the end of their stroke. At the beginning of said stroke and up to a point where the falling steam pressure on the piston only equals the resisting pressure of the weight, the excess of energy inthe steam cylinder is utilized in giving velocity to said weight, which velocity, .plus the decreasing steam pressure, causes the weight to continue upward until an equilibrium of forces brings it to rest.

The pistons start and stop slowly and acquire maximum velocity about midway of the up stroke.

In the accompanying drawings-Figure 1 is a side elevation, partly in section, of a single acting steam air compressor embodying the invention, certain minor parts being omitted for clearness of showing; Fig. 2 is a central vertical section, partly in elevation, of the air compressing cylinderand its appurtenances; Fig. 3 is a detail viewof a part of the steam valve gear; Fig. 4 is a side elevation of the steam cylinder and its appurtenances, certain parts being broken away; also an `airreceiver; Fig. 5 is a sectional plan view of the entire compressor, on a line corresponding to line car-b on Fig. 1; Fig. 6 is a detail section of a dashpot valve opening device; Fig. 7 is a vertical section of the upper part of an automatic cutoii' governing device.

Referrngrst to-Fig l: l designates' as a whole the air compressing cylinder; 2, as a whole, 'the 'power (steam) cylinder; 3, one of the two' standards supporting cylinder 2; 1, the steam piston; v6, the steam piston rod; 7, a heavy yoke mounted on and depending from said rod G; 8, the air piston rod, rigidly secured to the lower part of said yoke.

The steam piston rod 6 passes through the top cylinder head,where (in a single acting cylinder) no stuliing-box is required, and has an upward extension 6, for holding in position eXtra weights, as 9. The bottom of the yoke 7 is shown as enlarged, at 11, the purpose ot' which is simply to increase the weight of the yoke and lower its center orn gravity. By the combined weight of the yoke and other reciprocating parts the pistons are driven down, for the air compressing stroke.

' Referring to Fig. 2, 12 is the air compressing piston. The air induction "valves 13 are placed in this piston, instead of in the cylinder as is common. When seated, they are to be flush with the bottomof the piston. They are closed by springs 14. Loosely mounted on the piston r0d^8 is a member B, which is upheld by a set-collar-17A except when the piston rod is driven down far enough to bring it into contact with stops 1S, that arrest its descent. The member B comprises anan'nular top 16, a spider 19, arms 2O connecting the top to the spider, and bosses 21, milled to it loosely in air-cups 18 cast on the cylinder 1. Member B comprises also a tubular part 22 provided with a flange 23 adapted to impinge on the tops of the valve-stems 21 to hold said valves open by the weight of member B.

The upper end of the cylinder 1 being open, air will be drawn into the cylinder through-the opened valves 13, on the up stroke. .Toward the end of the up stroke, the valve-stems 24 will strike flange 23, and collar 17 will strike the part 16 of member B, carrying said member with it. Part 1G is recessed to receive collar 17 and form an air cushion for the purpose of obviating shocks.- On the -down fstroke, said valves will be held open by the weight of member B, until permitted to be closed by springs 25. The purpose of this operation is to permit the reciprocating parts to dropf with practically no resistance, for a part of the stroke, before compressingair in the cylinderA 1. The greater this free fall, relatively to the full stroke, the more highly the air will be compressed, as will be clear without theoretical statement.

The preferred arrangement of the eduction valves is shown. At the bottom of the cylinder proper, the bore is enlarged forming an annular recess 26. Above this recess, but separated from it by a metal partition, is an annular chamber 27. The valves 28 are seated in ports in said partition. These valves have stems 29, pressed down by springs housed in screw plugs 31, that are larger than the valves, to permit removal and insertion of the latter through the plug holes.

Connected to the annular chamber 27 is a largevalve chamber 32 in which is a large check-valve 33, pressed to its seat by'a heavy coiled spring 34, the compression of which is adjustable by turning a wheel 36. The delivery pipe 37 (Fig. 5) leads to the receiver 38, shown diagrammatically.

Below the air cylinder proper, Fig. 2, the cylinder is extended downward to contain a yieldable cylinder head 39. The cylinder is shouldered, as shown, to limit the upward motion of the head 39. The top of said head is always below the line 41, so that the piston 12, if driven down into the cylinder extension, will trap air between itself and the head 39, preventing violent contact between the two. The space below the head 39 is limited by the fixed cylinder bottom 42. An air pipe 43 connects this space with the annular compressed air chamber 27, and is rprovided with a check-valve 44.

When the piston 12 is driven down too far, it depresses the head 39 which highly compresses the air beneath it, which closes the check-valve 44. Thus the blow of the piston 12 is cushioned. Immediately the air under head 39 expands and drives said head upward, assisted by the high air pressure that is then free to enter through pipe 43 and valve 44. This high pressure will keep the head 39 from yielding under the compression produced by normal strokes of the piston. It will be understood that the function of head 39 is merely to prevent sudden shocks to the moving parts in case of a sudden drop in the pressure in the receiver.

As shown in Fig. 1, the steam cylinder 2` is provided with a similar device for cushioning the steam piston under the circumstances just mentioned. 46 is a yielding cylinder head, the space below which is connected by a pipe 47 (Fig. 4) to the steam chest 48.

The steam-chest 48 contains a steam-actuated admission valve, that is operated by a pilot valve in a housing 49. Said pilot valve has a shaft, on the ends of which are a rock-arm 51 and a starting lever 52. The valve arm 5l is automatically operated by means carried by the yoke 7.

53 is the valve-opening member, mounted on a vertical rod 54, secured at its lower end to a cylinder 56 carried by the yoke 7, and passing near its upper end through a guide 57, cast on a cylinder 58, supported by a bracket 59 on the steam cylinder 2. The valve-closing member 61 is mounted on a collar 61 slidablc on rod 54.-V

Collar 61 is engaged 'by a shipper 62. A

rod 62 is connected at its lower end to a pisl ton 63 in cylinder 56, and at its upperend has a head 63 sliding in cylinder 58. Rod 62 is hollow from end to end, and its lower end isclosed by a spring-closed valve 64. In the bottom vof cylinder 56 is a cock 66, which is always partly open. Adjacent the fixed cylinder 58 is a vessel 67, containing oil or water. Two pipes 68, 69, connected one above the other to cylinder 58, dip into the oil in vessel 67. The upper pipe 68 is provided with a check-valve 71. The entrance of the lower pipe 69 into the cylinder is so positioned that the end of thehead 63 will approximately cover it at the end of the normal stroke of the steam piston. The pipes 68, 69, the tubular rod 62, and cylinder 56 below piston 63are filled with oil. To receive any leakage overflow from the top of the cylinder, an annular cup 72 is provided, having a drain pipe 73. At each normal stroke, oil is drawn into the cylinder 58 through pipe 68, 69, and expelled through pipe 69. The check .valve 71 prevents discharge through pipe 68. But

when the pump stroke up is a little longer than normal, piston 63V passes over and closes the upper end of pipe 69, thus cutting ofi escape ofthe oil eXcept through valve 64, in the lower end of rod 62, where said oil serves to raise the piston 63 and ,y

rigidly connected part.

The point of cut-off of the steam admission valve depends on the vertical position of piston 63 in cylinder 56: this in turn depends on the quantity of liquid below said piston. The piston and its rod are to be made heavy enough to descend by gravity as the supporting liquid escapes through cock 66.

The normal operation of the parts is as follows: The continuous escape of oil through cock 66 lengthens the cuto slowly, which results in the steam piston and all connected parts being thrown up somewhat beyond the normal stroke end. This immediately shortens the cutoff by forcing oil under piston 63. This lengthening and shortening of the cuto goes on continuously-not at every stroke of the steam piston, but at intervals depending upon the l and the adjustment of `the cutoff eEected in the manner just described.

For regulation of'the'speed of the compressor, means for variably delaying the admission of steam at each stroke may be employed. Such means are shown in Figs. 4 and 5. It comprises a reciprocalble rod 74, passing through guides 76, 77; a link 78 pivotally connected to said rod and to the valve rock-arm 51; a dashpot 79 having a piston 81 with rod 82; a retarding device; a bell-crank 83 and a link vconnecting said bell-crank 83 torod 74. When rock-arm- 51 is turned from either eXtreme position,"link 78 moves rod 74 to the right, drawing up the dash-piston 81. The final downward movement of rock-arm 51 opens the pilot valve which opens the admission valve. The valve-closing member 61 as shown is a depending arm pivoted on a set-collar 61 and having va projection 61 adapted to engage the end of rock-arm 51. The valve opener, 53, descending, strikes the rock-arm 51 and pushes it below dead center but the actual opening of the valve is performed by atmospheric pressure on dash-piston 81, acting to complete the throw of the rock-arm 51.

The dash cylinder 79, has a smaller piston cylinder 86 below it, filled with oil and containing a piston `87, connected to piston 81 by a rod 88. In the oil piston are valves 89, opening downward for the purpose of allowing oil to flow from the upper to the lower side of said piston when said piston is ascending. The lower part of the smaller cylinder is formed with internal vertical grooves 91, the piston being guided by the surfaces between said grooves. 92 isa bypass connected above and below the piston 87. In bypass 92 are a hand-valve 93 and an automatically adjusted valve 94, adjusted by connection with an air pressure responsive device (indicated) 96, connected by a pipe 97 to the receiver 38. The parts are so adjusted that rising pressure in the receiver moves the valve 94 toward closed position.

The length of time required for piston 87 to descend below the upper end of the bypass grooves in the cylinder 86, and this in turnV depends upon the time required for the pistons 81and 87`to descend after having been drawn up, obviously depends on the adjustment of valves 93 and 94. Valve 93 is set to'pass the maximum quantity of oil required, while valve 94 controls the rate within that-limit. It willnow be clear that the adjustment of said valves will determine the number of beats of the compressor per unit of time.

The lost motion-device 99 in rod 82 has the function of, preventing breakage of parts when the rock-arm 51 is quickly turned past lits dead center. But said device 99 does not affect theoperative relations between the valve and the dash-pot piston; v

The cylinders 79, 86 and the device 96 are supported by brackets on the steam cylinder 2 and standard 3, respectively. The arrangement ofthe parts may be varied in many ways to perform the same functions.

The exhaust port of the steam cylinder is controlled by a suitable valve (not shown) in a housing 101. The valve has a shaft 102 on which is fixed a collar 103 (Fig. 3.) A rock-arm 104 is loosely mounted on said shaft '102 and has a segmental recess in which stands a lug 106 on collar 103. At one end of its throw the arm 104 strikes a spring 107 and is moved thereagainst by the valve-closing member 108, mounted on a rod 109, carried by the yoke 7. 0n the same rod is the valve-opening member 111. Member 108 projects farther than member 111', and would turn the arm 104 out of reach of member 111 were it not for the spring 107, which, as soon as the member 108 releases said arm, thro-ws the latter into the path ofthe ascending member 111, without moving the valve. Then the shoulder 112 engagesv lug 106, land when the valve-opener 111 turns said arm upward the exhaust valve is opened. This permits the reciprocating parts to drop.

In the upper part of the steam cylinder are air holes 113, that act as vents during the up stroke of the piston, and as inlets during the down stro-ke thereof. Said air holes are so located as to height that they will be covered by the piston at every abnormally long Lip-stroke. This will trap the air between the piston and the top cylinder head, forming an air cushion preventing the piston from striking the latter, should the operator in starting the pump turn in too much steam, and before the governing mechanism gets control.

The operation of the entire apparatus from the time of starting with low pressure in the receiver, will be as follows: The operator turns down the valve-pressure screw until the spring pressure on valve is equal to the air pressure that would be eX- erted thereon when the air in the receiver is at the required pressure. The object is to provide suitable resistance to the down stroke of the piston until the air has been compressed to the required pressure. The

compression regulator' member B is adjust- 3.

ed in accordance with the pressure to which the air is to be compressed. For higher pressures it is lowered, and for lower pressures it is raised. The steam throttle (not shown) is partially opened, and the admission valve is opened by means of the starting lever. Steam drives the piston up, with sufficient velocity so that the momentum of the reciprocating parts will carry the piston up until it is checked by the air cushion in vthe-top of the cylinder, notwithstanding the fact that the exhaust valve will have opened before the piston has ascended to the height referred to. The operator closes the admission valvev when or before the yoke starts to fall. 'Ihe first up stroke, just described, has caused the cutoff to be automatically shortened by the means hereinbefore described. rIhe operator manipulates the starting lever until the piston has made several up strokes, meanwhile observing the position of the cutoff member 51. TWhen said member has been raised to approximately correct position, no further manipulation of the starting lever will be necessary. The throttle may be fully opened. As the air pressure rises in the receiver, the operator turns back the wheel 36, gradually relaxing the pressure on the spring. When the required gage pressure has been reached the spring pressure is removed. The automatic steam cutoff, operating as hereinbefore described, insures the parts always being thrown up far enough to open the steam exhaust valve and give the moving weight the proper fall. Should the air pressure in the receiver materially drop, the steam and air pistons respectively will depress the yieldable heads 39, 46, below which the steam and air, respectively, will be compressed. rIhe pistons will rebound suiliciently to admit steam under the steam piston through the admission valve.

It is evident that the yoke 7 is not an essential part of a compressor embodying the invention, because if the steam and air pistons be directly connected by a weighted rod, no yoke will be necessary. The yoke construction has the advantages due to its own weight and of dispensing with a stuft'- ing box.

The air cylinder will of course be water jacketed (not shown).

I claim:

1. A direct acting vertical air-compressor, comprising a steam cylinder provided near its lower end with an admission port and valve, an automatic cuto for said valve, and an exhaust valve, an air compressing chamber below the cylinder, a piston therein, a piston within the cylinder and connected to the piston in the chamber and suitable weights for driving the pistons downwardly.

2. A direct acting vertical air compressor, comprising a steam cylinder, an air-cylinder, pistons in each working upwardly, a yoke member connecting said pistons, steam admission valves, and an automatically operated variable cut-off for the same controlled by movement of the yoke member whereby said steam is permitted to fully expand and produce its maximum efficient work in lifting the weight, air piston and Connecting means, the return by gravity of such parts effecting the air-compressing function.

3. In a direct acting vertical air compressor, the combination with a steam admission valve, of means for governing the trolled by receiver pressure for variably delaying the opening 01"' said valve after each down stroke of the compressor.-

5. In a direct acting vertical yair compressor, the combination with a steam admission valve, o means for` governing the number of beats of the compressor per unit of time, said means comprising means for variably delaying the opening of said valve after each down stroke of the compressor, and a hand-valve -for adjusting said delay.

6. In a direct acting vertical air compressor, the combination with anair' compressing cylinder and piston, means for reciprocating said piston, Vmeans for admitting air into the cylinder during the up stroke of the piston, and means for permitting the escape of a part of said air from the cylinder to atmosphere during the compression stroke before compression begins.

7. In a direct acting vertical air compressor, the combination with an air compressing cylinder and piston, means for reciprocating said piston,'means for admitting air into the cylinder during the up stroke of the piston, and means for permitting the escape of a part or' this air through the piston to atmosphere during the compression stroke before compression begins.

S. In a direct acting vertical air compressor, the combination with an air compressing cylinder, of an air compressing piston therein, having an air-admission valve opening downward; and means for automatically holding said valve open during a part of the compression stroke.

9. In a direct acting vertical air compressor, the combination with an air compressing cylinder, of an air compressing piston therein, having an air-admission valve opening downward; and means carried by the piston rod for automatically holding said valve open during a part of the compression stroke.

l0. In a direct acting vertical air compressor, the combination with an air compressing cylinder, of an air compressing piston therein, havingl an air-admission valve opening downward; a member loosely mounted on the piston rod, adapted to hold open said valve by pressure thereon, and a i support for said member, carried by the piston rod.

1l. In a direct acting vertical air compressor, the combination with an air com pressing cylinder, of an air compressing plston therein, having an air-admission valve opening downward; a member loosely mounted on the piston rod, adapted to hold open said valve by pressure thereon, and a stop for limiting the descent of said member during the compression stroke of the piston.

12. In a direct acting vertical air compressor, the combination with an air-compressing cylinder, of an air compressing piston therein, having an air-admission valve; a vertically movable member, adapted to hold open said valve by pressure thereon, a support for said member, carried by the piston rod, and a stop for limiting the descent of said member during the down stroke of the piston.

18. In a direct acting vertical air coml pressor, the combination with an air-compressing cylinder, the piston therein, having an air-admission valve; a vertically movable member adapted to hold open said valve by pressure thereon, during a part of the compressing stroke of the piston; and a stop for limiting the descent of said member whereby said valve will automatically close at a certain point in the compressing stroke.

14. In a direct acting vertical air compressor, the combination with an air-compressing cylinder, the piston therein, having an air admission valve; a vertically movable member loosely mounted on the piston rod and adapted to hold open said valve by pressure thereon, during a part of the compressing stroke of the piston; and a stop for limiting the descent of said member whereby said valve will automatically close at a certain point in the compressing stroke.

15. In a direct acting vertical air compressor, the combination with the steam admission and exhaust valves and the compressing cylinder, of means governing the number of beats of the compressor per unit of time, said means comprising means for variably delaying the opening of 'Said valve after each down stroke of the compressor, and means for variably delaying the closing of the admission valve.

1G. In a direct acting vertical air compressor, the combination with the steam admission and exhaust valves and the compressing cylinder, of means for governing the number of beats of the compressor per unit of time, said means comprising means for variably delaying the opening of said valves after each down stroke of the compressor, and a hand valve for adjusting the delay in opening the admission valve.

17. In a direct acting vertical compressor, the combination with an air compressing cylinder, a piston therein, having an admission valve, a vertically movable member adapted to open said valve by pressure thereon during a part ofthe compression stroke of the said piston, and means for limiting the descent of said member, whereby the said valve will automatically close at a certain point in the compressing stroke.

18. In a direct acting vertical air compressor, the combination with an air `compressing cylinder, a piston therein having an air admission valve, a movable member loosely mounted on the piston rod and adapted to hold said valve by pressure thereon during a part of the compressing stroke of the piston, means for limiting the descent'of said member, whereby said valve will automatically close at a certain point in the compressing stroke.

KENNEDY DOUGAN.

Witnesses:

S. SHUFELDT, K. IMBODEN.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents. Washington, D. C. 

